1. Field of the Invention
Aspects of the present invention relate to a manufacturing method of a liquid crystal display device, and more particularly to a manufacturing method of a liquid crystal display device which may laminate two or more multipiece boards by way of a sealing material, perform necessary treatment steps and separate the two or more multipiece boards into respective liquid crystal cells by cutting.
2. Description of the Related Art
A liquid crystal display device (panel) forms an envelope using a pair of substrates which are arranged to face each other by way of liquid crystal, wherein the liquid crystal is sealed by a sealing material which is also used for fixing the respective substrates.
A region surrounded by the sealing material may constitute a liquid crystal display region. Pixels may use the liquid crystal as one constitutional element and are formed in a matrix array on a liquid-crystal-side surface of each substrate in the region.
Further, such a liquid crystal display device has been manufactured recently using a method which is referred to as so-called multiple-cell manufacture or multiple-face manufacture for enhancing the efficiency of the manufacture.
That is, a pair of large-sized boards (multipiece boards) is prepared, and the constitution that is used for a region for forming each liquid crystal display device is applied to liquid-crystal-side surfaces of the respective large-sized boards.
Further, a sealing material (also referred to as an individual sealing material in some cases) is formed on the liquid-crystal-side surface of one large-sized board such that the sealing material surrounds at least the liquid crystal display region of each liquid crystal display device, another large-sized board is arranged to face one large-sized board by way of the sealing material, and the pair of large-sized boards is laminated to each other by curing the sealing material.
Then, by cutting the pair of large-sized boards, the large-sized boards are separated into a plurality of liquid crystal cells.
Here, in the lamination of the pair of large-sized boards, there may be a case in which a so-called gap adjustment step which sets an inter-space distance between the pair of large-sized boards to a fixed value, and a step which sets a thickness of at least one large-sized board out of the pair of large-sized boards to a predetermined thickness by surface polishing (chemical polishing) using an etchant before separation of the large-sized boards into the respective liquid crystal cells.
In such a case, before laminating the pair of large-sized boards, on the liquid-crystal-side surface of one large-sized board, in addition to the above-mentioned individual sealing material, a sealing material (also referred to as an outer peripheral sealing material in some cases) which surrounds the respective individual sealing materials and forms an opening in a portion thereof is formed.
In performing the above-mentioned gap adjustment, pressure inside the outer peripheral sealing material is reduced through the opening formed in the outer peripheral sealing material and, in performing the chemical polishing, the opening of the outer peripheral sealing material is sealed with a sealant thus preventing the intrusion of the etchant to the inside of the outer peripheral sealing material.
Such a manufacturing method of a liquid crystal display device is disclosed in JP-A-2001-337334 (patent document 1), for example. Another manufacturing method of a liquid crystal display device is disclosed in JP-A-5-5891 (patent document 2), for example. In the above-mentioned manufacturing method of a liquid crystal display device, when the opening of the outer peripheral sealing material is sealed with the sealant, there may be a case in which end surfaces of the pair of large-sized boards in the vicinity of the opening are covered with the sealant material and, further, the sealing material extends to and is adhered to surfaces of the pair of large-sized boards on a side opposite to a side where the outer peripheral sealing material is formed.
When a thickness of the large-sized board is decreased by applying surface polishing to at least one of the large-sized boards in such a state, the sealant which extends to and is adhered to the surface of the large-sized board on the side opposite to the side where the outer peripheral sealing material is formed remains in a state that the sealing material largely projects from the surface to which the surface polishing is applied.
When the pair of large-sized boards is placed on a base in a lying posture in such a state, the base and the projecting sealant come into contact with each other and hence, there arises a drawback that the large-sized board is easily broken due to a moment generated by such a contact.
In view of the above, there has been a demand for a technique which can, in sealing the opening formed in the outer peripheral sealing material using the sealant, form the sealant while preventing the sealant from covering end surfaces of the pair of large-sized boards thus obviating breaking of the respective large-sized boards.
Accordingly, it is an object of the present invention to provide a manufacturing method of a liquid crystal display device which can obviate breaking of two or more multipiece boards attributed to a sealant which may seal an opening formed in an outer peripheral sealing material.
To achieve the above-mentioned object, aspects of the present invention may use a sealing material which is referred to as a weir sealing material in this specification.